Refrigerating apparatus



July 29, 1924.

' K. L. CURTIS REFRIGERATING APPARATUS Filed Aug; 12, 1922 3Sheets-Sheet 1 IN VEN TOR 06 W BY 1; ATTORNEYS juiy 29; 192% K. L.CURTIS REFRIGERATING APPARATUS.

3v Sheets-Sheet. 2

Filed Aug. 12

f M 0 I V BY Z ATTORNEYS K. L. CURTIS REFRIGERATING APPARATUS Filed Aug.12, :1922 3 Sheets-Sheet 5 Jul 29, 1924.

is one by means of which a suitab Patented July 22, L924.

carts!) STATES xnmmrn L. scams, or new YORK, N. Y.

BEI'BIGERLTING APPARATUS.

Application filed August 12, 1922. Serial 110. 581,804.

To all whom it may concern:

Be it known that I, KENNETH L. CURTIS,

a citizen of the United States and resident of the city of New York,boron h of Manhattan, county and State of New provements inRefrigerating Apparatus, of which the followin s a specification.

This invention re ates to refrigerating apparatus.

An object of the invention is the provision of an improved andsimplified refrlger'ating apparatus which is particularly adapted formaintaining a refrigerator or cooler intended for containing foods orliquid, etc., at a suitable temperature. The apparatus e liquidrefrigerant water being preferred is placed in a closed chamber andevaporated therefrom, the chamber in the preferred embodiment of theinvention bein located within the space to be refrigerate and therefrigerant being evaporated in such manner as to constantly maintainthe desired low temperature in the refri rator. 'Apparatus embodying theinvention, due to its automatic and reliable operation, is espe ciallyuseful for family refrigerators.

This application is in part a continuation of my copending applicationSerial No. 539,881, filed February 28, 1922, for process and apparatusfor refrigeration;

According to the preferred embodiment -of theinvention as hereinafterdescribed, 35

a relatively high vacuum is maintained in the refrigerant chamber,suflicient to readily evaporate the water at a rate that will maintainthe refrigerant at a low temperature somewhat above the freezing point,and this without drivingthe vacuum pum at too high a speed. The waterinthe re rigerant chamber is maintained 'at a substantially constantlevel, and the air in the refrigerator is caused to circulate by passingupwardly and thence through openings traversing the refrigerant chamberin the upper part of the refrigerator, from which upper part the airagain descends.v I

The invention consists in the novel few tures, arrangements,construction and combinations of parts hereinafter described accordingto the preferred embodiment there- I of, and the invention'will be moreparticularly pointed out in theappended claims.

Further objects and advantages of the inork, have invented certain newand useful Im- 'into the c amber 1 by a following description taken inconnection I with the accompanying drawings illustratin by way ofexampl'ethe present preferred em odiment and two modifications ofapparatus comprising the invention, and in which Fig. 1 represents asomewhat diagrammatic view, partly in side elevation and partly insection, of the entire apparatus;

Fig. 2 is an enlar ed section taken on lines 2-2 of Fig. 1, il ustratingthe vacuum pumping apparatus at one point in its operation' c Fig. 3 isa sectional view similar to that shown in Fig. 2, illustrating thevacuum pumping apparatus at another point in its operation' .Fig. 4 1s asection taken on line 4-4 of Fig.3;

ig. 5 is a partial enlarged sectional view correspondingto the u per artof Fig, 2; Fig. 6 is a partial en 'arge sectional view corresponding. tothe upper part of Fig. 3;

and v Figs. 7, Sand 9 show modificationsof the refrigerator. Inaccordance with the invention, a liquid refrigerating medium, preferablywater, is

fed mto a chamber which is located in a.

space-to be cooled. I :have illustrated a closed chamber, or container,1,. located within a refrigerator 2 adapted for containing food, 'etc.,as in the usual domestic ice- The container 1 is box, or refrigerator.preferably located within the refrigerator near the'upper portion of theinterior thereof, and may be supported by suitable sup-.

aoT

ports 3, 3, which are preferably spacedinwardly somewhat from the outerwalls of the refrigerator.' The liquid refri ratin H medium, referablywater, as state is fe i e 4. Meansmust be provided for 'mamtammg thesupply of or liquid level is maintained at a constant desired level, asillustrated for example at 5, by

means of a float valve, the valve 6 being tainer 1 and having an arm 7carrying a float 8 secured thereto, the valve 6 closing when the liquidreaches the desired level and opening when the level falls, in the wellknown manner. vention will more fully appear from the" A continuouslydriven suction pump is illustrated as -pivoted to the wall ofconconnected by pipe 9 to the interior of container 1. A partial vacuumis maintained in chamber 1 by the operation of this pump which causesthe refrigerating medium to evaporate and thus to give up heat, the-.through and opening at both ends into the space to be refrigerated. Themembers 3 which serve as supports for chamber 1 also preferably serve aspartitions extending from side to side of the refrigerator with openings11 at the bottom thereof, so that when the device is in operation thewarmer air will pass upwardly through the space between partitions 3 andthe outer Walls, pass downwardly through the pipes or passages 10 whenthe heat is abstracted, and through the holes in shelves 12 and openings11, the air then again passing up along the outside passages. Therefrigerator may be provided with perforated shelves 12 in the usualmanner.

The vacuum pumping apparatus is shown as contained within the cylinder13 and the crank case 14. The vacuum producing or suction apparatus isof improved or novel design, constituting one of the features of theinvention, and is particularly well adapted to produce an exceedinglylow vacuum in chamber 1, which is necessary for or highly desirable inthe operation of the system.

The vacuum pump which is preferably used combines a zero-clearanceoutlet valve and a mechanically operated inlet valve. The zero-clearanceis obtained b making the outlet valve extend over the ull diameter ofthe cylinder so that the piston may move to the extreme end of thecylinder or ,tom'ary with sleeve valves.

even over-travel without doing any damage. The inlet valve preferablytakes the form of a sleeve which seals the inlet opening by seating atits end in the manner of a poppet valve and not by sliding over a portto entirely cover or uncover the same, as is cus- By the use of amechanically operated inlet valve and an outlet valve of the characterreferred to It am able to obtain great etficiency and may produce anexceedingly low vacuum. By. a mechanicallyfoperated inlet valve I meanone which 0 crates by mechanical means, independent et any difference ofpressure on the opposite sides of the same, so that operation of thesame will be certain even when operating under conditions of suchextreme vacuum, that there would not be enough pressure on either sideof a valve to open the same at any time. e

In the preferred form of the apparatus, as illustrated, the vacuum pumpapparatus comprises a pair of cylinders 13 and 15 which are secured toan air-tight crank case 14, the. cylinder 13 being shown as mounted onthe upper end of the crank case, with its lower end opening into thesame, while the cylinder 15 is mounted within the lower portion of thecrank case. The pistons of the two cylinders are connected to operate inunison, the piston 16 of the upper cylinder serving to draw water vapor,or generally speaking, the vapor of the liquid refrigerant, from chamber1 in the refrigerator and to discharge the contents of the crank casethrough pipe connection 18 into a suitable receptacle 19. The twocylinders are proferably the same in their construction, except that thelower is much smaller than the upper one.

The exhaust valves 20 and 21 of the cylinders '13 and 15 are preferablyboth of the full diameters of the cylinders and may be considered asmovable cylinder heads. They are held in place by springs 22 in the caseof the upper cylinder, and 23 in the case of form of sleeves as shown,the sleeve valve of the upper cylinder 13 being indicated at 24 and thesleeve valve of the lower cylinder being shown at 25. These sleevessurround the pistons and form in effect the cylinder walls. The uppersleeve 24 is preferably provided witlran inclined surface 26 at itsupper end which is adapted to seat against a correspondingly shapedsurface 27 on the valve seat 28, while the lower sleeve 25 is providedwith a similarly shaped lower end surface 29 which seats against asimilar seating surface on the seat 30. The sleeves are preferably movedin one direction by a cam or similar mechanical device, and in the otherdirection by spring action.

In the preferred form of the device, as illustrated, the two cylinders13 and 15 are diametrically opposed to each other and the two pistonsare operated in unison from the same wrist pin. As illustrated, the twopistons may e connected together by a rod 31 in axial alignment withboth of the same,

a connecting rod 32 being pivotally connect- 31 while thelowcr end ofthe connecting rod secured respectively to' the lower end of the uppersleeve and the upper end of the lower sleeve, these clamps being securedtogether by rods 39 extending between the same (see Fig. 4). Disk 35 ispreferably formed as a cam or eccentric, 'a roller 40 resting againstthe outer surface thereof. Preferably roller 40 is'carried by an arm 41having downwardly extending portion 44- above the cam disk 35,.ar1n 41being ivotall secured at its1outer end, at'42 to .ie cran case. The camdiskand roller 40 are utilized for moving the sleeve valves in onedirection, while springs are used for moving the sleeves in the otherdirection, suitable springs being indicated at 43 secured at theiropposite ends .to the clamping member 38 and the cylinder 15.

A push rod 45 for actuating the sleeve valves rests on or is secured tothe upper portionof arm 41. Preferably push rod 45 is formed as a tube,for a urpose to be explained hereafter, this tu extending through asuitable openin in the clamping member 37, through an a igned opening inthe top member 46 of the crank case and into an aligned bore orpassage47 formed in cylinder 13, in which it is guided. Preferably push rod 45operates the sleeve valves through a spring 48 (see Figs. 2 and -3)which must be sufliciently 'stifl' to move the sleeves against the pullof springs 43 and yet be capable of being compressed by a slightover-travel of push rod 45 itself, 'so as to preventpossible damage ofthe parts in case the push rod tends to over-travel slightly for anyreason. ,Spring 48 may surround the rod or tubular member 45 between acup or abutment 49 secured to the rod, at one end, and a on 50 attheother end which bears against t e clamping member 37. Accordingly,both sleeves will be moved upwardly by cam.35 and will be moveddownwardly by springs 43 as soon as such movement is permitted by cam 35during each operation of the pistons. In the operation of the device asso far described, the pipe connection 9 which leads to the evaporatingchamber 1 in the refriger'ator, is connected through the opening 51 inthe upper head-of cylinder 13 with a passage 52 which leads into theinterior of cylinder 13, above piston 16, when sleeve 24 is away fromits seat 27, as shown in Fig. 6. In the regular operation of the system,air and water vapor, or other gases, will be sucked into the space abovepiston 16 on the descending stroke of the latter, as shown in Figs. 3and 6, inlet valve 24 then being opened and outlet valve 20 closed.Valve 24 will be moved upwardly against its seat about the time thatpiston 16 starts on its return or upward movement so that outlet valve20 will be moved from its seat against the pressure of springs 22 andthe contents of the cylinder above the piston will be forced intopassage 47 previously referred to. The gases pass from passage 47 intothe tubular member 45 which extends into the lower end of the same andpass out through an opening 53 in member 45 into the interior of theair-tight crank case.

- Piston 17 of the lower cylinder will be rising on its intake. strokeas the upper piston is moving upwardly on its expelling stroke.Condensed water, or air and gases 1n the crank case, and surplus 011will pass through an opening 54 which extends through cylinder 15 of thelower pump member into an annular space 55 formed in the cylinder 15surrounding sleeve 25. The sleeve being raised from its seat, as shownin Fig. 2, this material "will be drawn into the interior of thecylinder, and when sleeve valve 25 closes and piston '17 descends, the

outlet Valve 21 will-open and this material will be forced out throughpipe 18 into the container 19 shown in Fig. 1. v

It will be noted that the outlet valves 20 and 21 of the two cylindersextend across the entire diameter of the cylinders and constitute whatmay be termed zero-clearance outlet valves, since the pistons may travelon their exhaust strokes to the full end of the cylinders, or may evenover-travel.

Valves 20 and 21 may be considered as mov-' able cylinder heads.

The pump (pistons are 'designedto o erate at hi h s cc in the systemdescribe and consi era le ower would be required if the upper piston adto operate at this speed to "withdraw air from chamber 1 at thebeginning of the operation, when the entire systern is filled with airat atmospheric pressure. Also the air thus drawn from the evaporatingchamber 1 by the large upper cylinder and discharged into the crank casewould be more than the smaller lower cyl-.

inder could'remove in time to prevent the building up of a high pressurein the crank case, which would further increase the power required.Accordingly, in the preferred form of the invention the lower cylinderalone is utilized at the be 'nning' of the operation, the lower cylinerthen withdrawing air from the interior of the crank ease and throughconnection 47 and a bypass connection 56 from the container 1. Pumpcylinder 15 is considerably smaller in diameter than the upper pumpcylinder'and very little power is required to operate the same even withthe entire apparatus full; of air. Automatic means are provided, in thepreferred form of the invention, to become r effective when a suflicientvacuum has been established in the system, to cut in the upper cylinderso that from this time on the larger capacity upper cylinder will beeffective for maintaining vacuum and evaporating the water gases fromchamber 1, the lower chamber serving from this time on merely to removethe air or gas, oil and condensed liquid from the crank case.

In the form of construction describedbypass 56 extends from the inletopening 51 through a valve opening 56', 57, into the space 58 at theupper end of the cylinder in which the outlet valve 20 is seated, thisspace,

58 opening into the passage 47 which leads to the crank case. A valve 59is positioned to seal the opening 56 extending from the horizontalportion of bypass 56 into the. recess 57, when a suflicient vacuum hasbeen established in the. system, so as to shut off the bypass. I

This valve 59 rests on a pile of air-tight containers 60 (Figs. 5 and 6)which rests on a support 61 which extends across the. constructionwithin space 58. Containers 60 are thin hollow members, of what may betermed pill box construction, preferably formed of very thin metal.

They are filled with air at atmospheric pressure, and will lie flat oneach other on support 61 when the pressure surrounding them in space 58and bypass 56 is'atmospheric, in which case .an opening will be providedover and around the containers, as is shown in Fig. 5. When thiscondition exists the lower pump cyl-- inder will draw directly throughpassage 47 and bypass 56, from chamber 1, and the upper After the lowerpump has operated suiiiciently to reduce the pressure in the crank case,containers 60 will expand because of the unbalanced pressure of the airconfined inside the same, and valve 59 will be lifted and held againstits seat at the top of space 57, as is shown in Fig. 6, whereby thebypass 56 will be closed and the upper pump cylinder rendered effective;

In the preferred construction of apparatus the wrist pin 33v ispreferably mounted between ball bearings 62 and the crank pin issimilarly provided with ball bearings (not shown). The crank shaft 36 ispreferably provided with a step bearing 63 to take the thrust caused bythe vacuum in the crank case, the step bearing forming a seal andpreventing air from leaking into the crank case at-this point. Oil maybe supplied to the face of this ste bearing through pipe 64, the '1being slowysucke into the crank case a ong the surface of the crank in?36 and thereby lubricating the crank The-remaining parts of-the pumpinga paratus are preferably lubricated by a. sing e oil supply pipe 65,indicated in Figs. 1 and pump cylinder will be inoperative.

also sucked down from recess 66 into the crank case, where it issplashed by the crank disk 35 so as to reach every movmg part in thecrank case.

The receptacle 19 into which the lower cylinder 15 discharges serves asan oil reservoir and also as a separator to recoverthe surplus oil fromthe discharge of the pump. The condensed water vapor from the crankcase, when water is the refrigerating fluid used, settles to the bottomof vessel 19, as is indicated at 66, the oil rising above the water, asis indicated at 67. The oil is drawn upwardly from this space by pipe65, previously referred to, and is used over again. The water is forcedupwardly in a trap 68, by the weight of the oil 67 above the same invessel 19, the water flowing out through' a pipe 69 in trap 68.

In Fig. 7 I have shown a modification of the invention for use inrefrigerator apparatus, more correctly known as water or liquid coolers.In this a paratus the refrigerator chamber, space or container for thesubstance to be chilled, such for example as water, is indicated .by thecoil 72 which may be connected at one end to a suitable source of water,and having the outlet 73. This takes the place of the refrigeratorchamber or space for foods and the like, shown in the first form of theinvention, and conversely to the first form of the invention, instead ofthe refrigerant chamber being lo cated wholly within the refrigeratorchamber in this modification, the coil 7 2 is located within therefrigerant chamber 1 which, as in the first case, has its outer wallsuitably packed with insulating material and may be provided with anysuitable opening-thereto (not shown) for cleaning the. same. 'Thisrefrigerant chamber, as in the first modification, is provided with anoutlet pipe 9' to which the pumping apparatus 13 is connected, exactlyas in the first modification, and the chamber is also prm vided with arefrigerant inlet. pipe 4 connected to a suitable source of'water suchas a city water supply, and the level of water in the chamber ismaintained by the valve 6' controlled through the float 8, all asheretofore described in connection with the first form. The method ofoperation, except for the differences of construction pointed out, isidentical to that already described in connection with the first form.

4 In 8 and 9 I have shown another modification of the invention whereinthe refrigerator chamber consists of an inner between the chamber 7 4and the outer metal wall of the chamber 1", which space constitutes therefrigerant chamber. This refrigerant chamber is provided with asuitably packed outer wall 70, and is connected with indicated the pumpthrough the pipe 9" in the manner heretofore described, and therefrigerant level is automatically maintained as heretofore described,by the valve 6" withthe float 8. This valve 6" in this modification iscontrolled by a pair of floats 8"8,"

as shown in Fig. 9, connected through acircular member to the valve, soas to properly equalize valve 6".

The refrigerator chamber is provided with any-suitable openings such asthe cover 76, suitably, packed in the same manner as for: the walls ofthe refrigerant the pressure exerted on the chamber.

The refrigerating apparatus described is inherently self regulating,because as the temperature of the water in chamber 1 is lowered, thewater vapor withdrawn therefrom'through pipe 9 becomes less dense and asthe amount of cooling produced in chamber 1 at a given pumping speed isdirectly proportional to the amount of vapor removed, it is directlyproportional to the density of the vapor. For example, at 40 F.temperatureone pound of steam occupies 2438 cubic feet, and at 32 F. itoccupies 3294, cubic feet. The removal of one pound of steam willproduce practically the same amount of cooling at either temperaremovedwill have a greater density.

ture.

When a greater cooling effect is required in the refrigerator, that is,for example when food products are placed in the refrigerator whichrequire cooling, the temperature of water chamber 1 will irise, and theva pfir e suction pump runs at constant speed and in removing the vaporof greater. density it removesmore heat, which is the condition desired.In a like manner when the tem erature of the chamber 1 falls, less heatWlll be removed therefrom because of the vapor removed being of lesserdensity. As stated, the refrigerant will not drop below the freezingpoint because the capacity of the pump'at its constant speed, is suchthat at the lower room temperatures which the refrigerant' willencounter, there will not be suflicient evacuation to freeze therefrigerant, and at the. higher temperatures the inherent property ofthe saturated vapor as above pointed out, will operate as stated inmaintaining the refrigerant temperature within the desired range. Thetemperature of the refrigerator will accordingly be maintained within anarrow range, this range be ing not sufliciently great to interfere withthe satisfactory operation of 'the apparatus.

As the pump runs continuously no auto-- maticdevices for starting andstopping the driving motor are necessary. This 1s an important featurein household refrigeration because it avoids throwing heavy loads on thehouse circuit which would occur in starting the driving motor. Mosthouses are equipped only with a lighting circuit with fuses of a limitedcapacity suitable to pro- -tect such wiring, and if motors were put onthese circuits which were intermittently started without any extraprecaution, the result would probably be a blowing of the fuse oradangerous heating of the circuits whenever the motor was started.

As heretofore stated, this application is in part a continuation of myco-pending application Serial No. 539,881, filed February 28, 1922, forprocess and apparatus for refrigeration. In this application I claim therefrigerating apparatus or refrigerating system, together with variouscombinations andfeatures of the system as a refrigerating system, but Imake no claim in this application to the pumping apparatus per se, sincethat forms the subject matter of a co-pending application Serial Number582,128, filed on August 16, 1922; nor to the method of refrigerationcarried out by the system or re-' frigerating apparatus, since claims tothe method of refrigerating constitute the subject matter of theaforesaid parent application Serial No. 539,881, filed February 28,1922. These later applications have been filed because of requirementby' the Patent Oflice of division among these different sets of claimsin the parent application.

It is believed that the apparatus described and the operation of thesame, as Well as the method of refrigerating carried out thereby, willbe readily understood from the foregoing description.

While I have described my invention in detail in connection with thepresent preferred embodiments thereof as shown in the drawings, it willbe understood by those skilled in the art, after understanding myinvention, thatv'arious changes and modifications may be made thereinwithout departing from the spirit or scope of the invention, and I aimin the appended claims to cover all such modifications as are within thepurview of the invention.

Having thus described my invention, what I claim as new and desire to,secure by chamber and having a number of air passages therethroughforthe circulation of air, automatic means for maintaming the level ofrefrigerant in said refrigerant chamber, an air-tight crank case, aconstant speed suct1on pump with means connecting the same -to saidrefrigerant chamber and to said crank case for pumping gases from thechamber and delivering same to the crank case, and a pump within saidcrank case for withdrawing gases, oil and condensed liquid therefrom.

2. In refrigerating apparatus, the combination of a refrigeratingchamber, a refrigerant chamber within said refrigerating chamber andhaving a number of air passages therethrough for the circulation of air,

15 automatic means for maintaining the level of refrigerant in saidrefrigerant chamber, acompound suction pump connected with therefrigerant chamber for sucking vapors from the refrigerant to evaporatethe latter from the chamber, and means controlled by pressurein therefrigerant chamber to render the pump single acting at a predeter minedpressure in the refrigerant chamber whereby the pump is automaticallycontrolled to prevent excess load thereon due to compound action of thepump at high pressures.

In testimony whereof I have signed my name to this specification.

KENNETH L. CURTIS.

